1. Field of the Invention
This invention relates to a converter arranged to be mounted between a camera body and a lens barrel.
2. Description of the Related Art
As a result of the recent advancement of the arts related to actuators, sensors, electronic circuits, etc., video cameras as well as still cameras have come to be mostly arranged to perform automatic focusing and automatic exposure control.
In the field of the single-lens reflex still camera, it has been known to arrange an interchangeable lens to permit control and driving actions on a diaphragm and a focusing lens to be mechanically accomplished from a camera body in a manner as disclosed in Japanese Patent Publication No. SHO 63-67171 or No. SHO 63-67172.
With respect to a method for driving the diaphragm and the lens of the lens-interchangeable type single-lens reflex camera, a camera system arranged to drive the lens and the diaphragm solely by electrical connection while obviating the necessity of any mechanical interlocking arrangement between the camera body and the lens barrel has been proposed, for example, as disclosed in Japanese Patent Publication No. HEI 1-17139. According to this camera system, each individual lens is arranged to have its own actuator. This arrangement enables the camera system to have many advantages in respect to the speed and accuracy of focusing, elimination of operation noises, etc.
Meanwhile, compact video cameras have become more and more popular. As a result, the need for arranging video cameras to permit use of interchangeable lenses has increased. It is desirable that such a lens-interchangeable video camera is also arranged like the above-stated camera system wherein only electrical connection is required and each lens has its own actuator.
There is also a great need for use on the above-stated camera body of such interchangeable lenses of the manual operating type that are on the market. It has been, however, sometimes impossible to meet the need because of such a problem as a difference in shape of mounts or because the lens mounted on the camera body cannot be electrically confirmed.
Further, it would be highly convenient for the users that an interchangeable lens designed for a camera system of the kind having the interchangeable lens mechanically interlocked with the camera body is arranged to be usable also for the camera body of a camera system of the above-stated kind operating solely by electrically connecting the camera body to the interchangeable lens. However, such arrangement has not been practicalized.